As disclosed in the above identified applications, various methods and apparatus may be employed for foam coating or adhesive bonding. Ordinarily, the foamable liquid compositions and blowing agents are contained in a pressure vessel. For instance, a paint composition is mixed with a fixed quantity of liquid blowing agent such as freon, butane, propane and the like, in a vessel of constant volume, strong enough to withstand the pressure of the blowing agents at the temperature of choice. However, as the foamed paint is dispensed from the vessel, usually by means of a dip tube inserted into the vessel and a release valve, each increment of foam is issued at a decreasing foam-volume radio in respect to the one preceeding it. The term "foam-volume ratio" is used in this context to mean the ratio of foam-volume to the volume of liquid before foaming. Reduction in foam-volume ratios upon dispensing foamable compositons from pressure containers cause a lack of process control in dispensing foamable compositions. As a result, coatings or adhesives of uniform or satisfactory quality are not achievable with present pressure containers. Furthermore, this foam dispensing problem makes it impractical to withdraw as much as even one-third to one-half the liquid volume from the vessel for foaming.